It is also pretty cheap at Walmart in gallon jugs. I decided to switch to canola oil because it has a higher flash point and ignition point and doesn't stink so much. It stinks even more when you burn it off in the tempering oven - definitely an outdoors job.
The motor oil is unpleasant to work with because you tend to get a lot of flames when quenching large parts, plus it stinks. I was getting a dark black finish at first quite by accident. When I first started hardening steel, I quenched my hot steel (844 C, 1550 F) in used motor oil because it was free. I make various hardened tools for my use and for sale. I have been using various methods to blacken steel and this one works well without any technical difficulties. place finished parts on rag and let coolĬheck out this great ehow article-which is where I learned a lot of this process! repeat process 2 or three times per part to achieve desired finishġ0. If you want an even finish, you should drop and retrieve each timeĩ. dropping the part and retrieving with pliers may seem unnecessary, but if you hold onto the part the whole time with the pliers, you will end up not blackening the bit clamped between the pliers. retrieve the part once again with the pliers. when oil has burned off and your part is a reddish color, drop it in the bowl of oil, or "quench" it in oil.Ĩ. it may light on fire but should also quickly burn out. note that during this part you will drip oil on/around the torch. The oil coating your part will ignite but will burn out soon. hold part over flame, moving slowly as to evenly burn off the oil. submerse a part completely in the oil and retrieve with pliersĦ. light torch and adjust flame to something manageableĥ. Make sure that you pour enough oil so that your part(s) can be completely submergedĤ. It really depends on your bowl and your part. pour motor oil into bowl, about 2 cups were more than enough for me. wear safety gear and bring fire extinguisher outside with you.just in caseģ. I laid out two so that I could separate finished from unfinished.Ģ. I have annotated them for clarification.ġ. Hopefully you can get an idea of the setup from the photos in this step. This is where the process needs to move outside for sure.